Photo courtesy of Konrad Schmidt
Central mudminnow - Common name
Umbra limi - Scientific name
Family - Umbridae- (mudminnows)
Status : S1, G5
IDENTIFICATION: The central mudminnow has a long, slender, cylindrical body. Adults are typically 2 to 4 inches long (50 to 100 mm). It has a dark colored body above ranging from dark olive-brown to blackish brown, with a white or yellow belly. It has several irregular dark vertical bars along its side, and the lateral line is absent. It has a rounded tail fin with a black vertical bar at the base. The dorsal fin is set well back on the body. Central mudminnows have small scales and soft fin rays. The breeding male has iridescent blue-green fins. The fish feels slimy and very soft when handled (carefully of course).
SIMILAR SPECIES FOUND IN SOUTH DAKOTA: The banded killifish and plains topminnow are similar to the central mudminnow, but these species are lighter colored and have an upward tilted mouth. The banded killifish has narrower, more regular olive brown vertical bars along its side. The plains topminnow does not have a dark, vertical bar at the base of its tail.
HABITS AND HABITAT: In eastern South Dakota the central mudminnow has been found in slow-moving streams and backwaters that are vegetated and have muddy substrates and organic debris. Mudminnows have a special characteristic for a fish in that they are capable of breathing air, which allows them to survive in stagnant poorly oxygenated waters that are unsuitable for most other fish species.
DISTRIBUTION: Distribution Map This species is common in the Great Lakes - St. Lawrence River, Hudson Bay, and Mississippi River drainages. In South Dakota the central mudminnow is found in isolated populations, on the very western edge of its range. Central mudminnows have been found on the Big Sioux Cotteaux in Blue Dog Lake and Owens Creek in Day and Roberts Counties. In the Minnesota River Basin central mudminnows have been found in the Yellowbank River and the North Fork of the Yellowbank River in Grant County, as well as in Lake Cochrane in Deuel County. There is record of central mudminnows occurring in Sixmile Creek in Brookings County in the Big Sioux River Basin, but the species has not been observed there since 1952 and is believed to be extirpated from this stream.
CAUSES OF CONCERN AND CONSERVATION MEASURES: In South Dakota the central mudminnow populations are rare and very unique, making up the very few isolated populations found in the Missouri River Basin